This invention relates to a heat exchanger using two fluids flowing in counter-current, and applicable more particularly to compressor heat pumps.
In such pumps, two heat-exchangers are used, one operating as a condenser and the other as an evaporator, i.e., two exchangers which operate in different heat exchange directions in relation to one another. In the case of a reversible heat pump, i.e. one for summer and winter operation, each exchanger must also operate as a condenser during part of the year and as an evaporator during the other part of the year.
To obtain optimum operation of such exchangers, irrespective of the heat exchange direction, the counter-current flow of the two fluids must be maintained in the two reverse operation cycles of the pump.
In the case of reversible compressor heat pumps in which the heat exchanges are effected between a refrigerant fluid and air in each of the two exchangers, there is no suitable arrangement of valve means which readily and inexpensively enables the counter-current heat exchange between air and the refrigerant fluid to be maintained in the two exchangers irrespective of the heat pump cycle, i.e., to reverse the direction of flow of one of the two fluids; or which enables the refrigerant fluid to be constantly injected in the gaseous phase in the top part of the exchanger acting as a condenser, and withdraw this fluid in the liquid phase from the bottom part of the exchanger acting as a condenser; or to enable pressure shocks to be attenuated when there is a change-over of the cycle.